Telephone system



Oct. 24, 1933. w. E. DARROW TELEPHONE SYSTEM Filed March 2, 1933 lNl/ENTOR W. E. DIRROW ATTORNEY Patented Get. 24, 1933 TELEPHONE SYSTEM Wirt Edward Darrow, Hollis, N. Y., assignor to American Telephone and Telegraph Company,

a corporation of New York Application March 2, 1933. Serial No. 659,405

10 Claims.

This invention relates to telephone systems and more particularly to universal cord circuits for interconnecting telephone lines of like or unlike character.

An object of the invention is to interconnect lines of like or or" unlike character and to provide supervision for said connections.

A feature of the present invention, whereby the foregoing object is attained, resides in a universal cord circuit having supervisory relays individual to each. end thereof, said relays controlling individual lamp signals on commonbattery connecions and serving as ring-01f relays on'magneto connections to lock up an auxiliary relay which controls a magneto disconnect signal.

In one embodiment of my invention, the com- ..ion battery supervisory lamps are used for common' battery supervision on common battery connections and for magneto disconnect and recall signals on magneto connections. In'another embodiment separate signal devices are used for common battery supervision and for magneto signaling.

The invention will be understood from the following description together with the accompanying figures of the drawing in which the twoembodiments of my invention are illustrated.

Figure 1 shows the embodiment in which the common battery supervisory lamps are used interchangeably for common battery supervision and for magneto signaling.

Fig. 2 shows the embodiment in which a separate signal lamp is used for the magneto signaling.

Circuit description In Fig. 1, A and B are subscribers common battery lines'and C and D are subscribers magneto lines. E is an operators universal cord circuit located at an operators position ataswitchboard at which are also located line jacks 100 and 101 of common battery lines A and '3, respec-- tively, and line jacks 102 and 103 of magneto lines C and 1), respectively. Associated with jack 100 is common battery line lamp 104 and with jack 102 is magneto drop signal 105.

An operators telephone circuit is associated with cord circuit E which is adapted to be connected thereto. Universal cord circuit E consists oi answering and calling cords comprising tip and ring talking conductors and sleeve conductors and terminating in connecting plugs 106 and 107 respectively. Condensers 108 and 109c0nnect the tip and ring talking conductors of the answering and calling cords, respectively.

Answering and calling sleeve relays 110 and 111 are associated with their respective ends of the cord and operate responsive to the connection of the sleeve to a grounded conductor. This occurs when their respective plugs are inserted into the jacks of common battery lines but not on connections to magneto lines.

Answering and calling supervisory relays 112 and 113 are provided with two windings and are normally bridged directly across the tip and ring conductors of their respective ends of the cord. In response to the operation of its associated sleeve relay, however, battery and ground are connected through a supervisory relay to the ring and tip conductors, respectively.

Auxiliary relay 114 can be energized over either of two circuits, the first extending through a front contact of the answering supervisory relay and back contact of the answering sleeve relay and the second extending through these respective contacts of the calling supervisory and sleeve relays. Relay 11 1 will be operated, therefore, only in response tov the operation of one of the supervisory relays. An advantage of this, arrangement resides in the delay given to the operationof relay 114 by the addition of the operating time of a supervisory relay. This de creases the possibility of fortuitous operation of relay 114 due to momentary impulses coming over the line or to the discharge of condensers 108 and 109. To further prevent accidental operation of relay 11 1 it may be designed with slowto-operate characteristics.

Upon operating, relay 114 will lockup under control of the cord circuit talk key 115.

Answering and calling supervisory-lamps 116 and 117 are controlled by their respective supervisory relays. They also are arranged to be controlled by auxiliary relay 114 when their associated plug terminals are connected to magneto line jacks and there is consequently no ground on the sleeve.

Fig. 2 shows the second embodiment of my invention in which a separate lamp is provided for magneto signaling. Universal cord circuit F is here understood to be associated with line circuits A, B, C and D and with the operators telephone circuit in the same manner as cord circuit E.

In cord circuit F a magneto signal lamp 218 will be lighted in response to the operation of' auxiliary relay 214. Common battery supervisory lamps 216 and-217 are controlled by their associated supervisory relays, only. Otherwise, corresponding elements of this cord are similar to those of cord circuit E.

1 is closed for the operation .of calling supervisory tion, the associated supervisory relay releases Operation The operation of the circuits shown in Fig. 1 is as follows:

Upon originating a call from common battery station A the subscriber removes the receiver from the switchhook thereby closing a circuit for battery over the line and through the contacts of the multiple jacks to light line lamp 10 1.

The operator, upon seeing lamp 104 lig ted, inserts plug 106 into jack 100 and operates talk key 115 to connect her telephone set to the cord.

Larnp 104 is extinguished by the opening of ring contacts of the jack and ground is connected to the sleeve by the closing of its'sleeve contacts. A circuit is thereby closed to operate answering sleeverelay 110 from battery, through the winding 01. relay 110, sleeve conductor of the answering cord, sleeve of plug 106, sleeve of jack 100 to ground through contacts 122 of said jack. Relay 110 operates connecting battery and ground to the cord through the windings of relay 112. A circuit is also closed to light lamp 116 from bat tery, through lamp 116, lower back contacts of relay 112, upper back contacts of relay 114, over the sleeve conductor to ground. Since the receiver is off the switchhook at the subscribers station, a circuit is closed to supply current to the subscribers transmitter over the line loop and hence to operate answering supervisory re lay 112. Relay 112, in operating, opens the energizing circuit for lamp 116 by opening its lower back contact but it does not close a circuit for the operation of relay 114 at its upper contact since the circuit is now open at the upper back contact of relay 110.

Upon ascertaining the number of station desired by the calling subscriber, and which we will here assume to be station 13, the operator performs th usual busy test by touching the tip or" her calling plug 107 to the sleeve of jack 101 connected to the called line. Finding the line idle the operator inserts plug 107 into jack 101. Calling sleeve relay 111 operates and calling supervisory lamp 117 lights over circuits similar to those described for the answering end of the cord. Calling supervisory relay 113 does not operate at this time, however, since the line circuit is open at subscribers station 13 where the receiver is still onthe switchhook.

The operator releases talk key 115, thereby disconnecting her telephone set from the cord, and momentarily operates ringing key-119 applying ringing current to the called line.

When the called subscriber answers a circuit relay 113 over the line loop. Relay. 113 operates and extinguishes lamp 117. The circuits are now in condition for conversation between common battery stations A. and B with transmitter battery being supplied through the windings of answering and calling supervisory relays 112 and 113 to stations A. and B, respectively.

Upon the subscriber at either station hanging up his receiver on completion of the conversa and lights its supervisory lamp as a disconnect signal to the operator. When the operator removes the plugs from the jacks in response to these signals the circuits return to normal.

In case magneto station D was the called station instead of common battery station 13, the operator will have inserted plug 107 into jack 103 after performing the sual busy test on the sleeve of thatjaclz. Since no ground is found on the sleeve or jack 103. relay 111 will not operate and lamp signal 165.

117 will remain dark. Relay 113' will remain bridged directly across the tip and ring conductors of the calling cord. I

When the subscriber at station D answers, current is supplied to his transmitter from the local battery at his station.

Upon termination of. the conversation, subscriber A hangs up and lamp 116 is lighted as previously described. Subscriber D, after hanging up, operates the magneto generator at his station for a short interval thereby sending an alternating current over the line. Relay 113 operates during the interval in response to this current closing a circuit for the energization of relay 114 as follows: From battery, through relay 11 1, upper front contacts of relay 113, upper back contacts of relay 111to ground. Relay 11 1 opcrates and establishes a holding circuit for itself from battery, through its own winding, its lower front contact, conductor 120, normally closed contact of talk key 115 to ground.

Operation of relay 114 does not'affect the lighted condition of answering supervisory lamp 116 since with the answering. cord connected to a common battery line, ground is connected to the sleeve conductorqand hence to both back and front upper contacts of relay 114. At its lower outer front contact, however, relay .11 connects ground to conductor 121 which is in the energizing circuit for calling supervisory lamp 117. When relay 113 releases upon the called subscriber discontinuing the operation of his magneto generator the circuit is completed for the lighting of lamp 117 as a signal to the operator;

The operator operates her talk' key 115 and challenges on the line, whereupon, receiving no reply she disconnects. The operation of the talk lcey opens the holding circuit'for relay 114 which causes it to release extinguishing lamp 117. Since lamp 117 can only be extinguished by the operation of the talk key the operator is forcedto challenge on all disconnections involving a magneto station. This insures attention from the operator in case the magneto subscriber had signaled for a recall.

When a subscriberat station C initiates a call he operates his magneto generator which sends current over the line to operate magneto drop The operator, noticing the signal, inserts plug 106 into jack '102 and restores the drop. Relays 110 and 112'remain unoperated and lamp 116 is not-lighted. On a call to station B or vD, the operation of the calling cord relays and lamp will be the same as previously described for these respective station's. Answering cord supervisory relay 112 will operate in response to the operation of the magneto at station C for a disconnect or recall signal. This will energize relay 1 1 1 and lamp 116 will be lighted on release of relay 1'12. Q If magneto stations C and D are connected; however, a disconnect or recall signal sent by either subscriber from his magneto generator will operate relay 114 and cause both calling and answering supervisory lamps 116 and 117 to light since both are inthis case under control of relay 11 1. The rest of the operation is the same as previously described.

The operation of cord circuit F in connection with the same line circuits and operators telephone circuit is the same as that of cord circuit The associated supervisory relay will operate on a magneto disconnect or recall signal energizing auxiliary relay 214 in the same'manner as described for -cord E. Relay 214, in operating, lights auxiliary lamp 218 to signal the'operator.

With the auxiliary lamp of cord F lighted the operator is informed immediately that she must challenge on the line to determine whether a recall is desired. With the arrangement shown in cordE she would be unable to distinguish between common battery disconnect signals which do not require a challenge and magneto signals which require one Without observing the type of line to which the cord is connected;

While the present invention is disclosed as embodied in certain specific arrangements, applicant does not wish to be limited by such disclosure, but desires to cover broadly all arrangements which come within the spirit and scope of the appended claims.

What is claimed is:

1. In a telephone system comprising lines of two different characters, a universal cord circuit for interconnecting any two of said lines, answering and calling connecting terminals for said cord circuit, a supervisory signal individual to each end of the cord, a supervisory relay individual to each end of the cord, a locking relay, signal means controlled thereby, and switching means adapted to connect each supervisory relay to control its respective supervisory signal when their associated connecting terminal is connected to a line of the first character and to connect said relay to control the initial energizing circuit for said locking relay when its associated terminal is connected to a line of the second character.

2. In a telephone system comprising magneto and common battery telephone lines, a universal cord circuit for interconnecting any two of said lines, answering and calling connecting terminals for said cord circuit, a supervisory signal individual to each end of the cord, a supervisory relay individual to each end of the cord, a lock- 1 ing relay, signal means controlled thereby, and

switching means adapted to connect each supervisory relay to control its respective supervisory signal when their associated connecting terminal is connected to a common battery line and to connect said relay to control the initial energizing circuit for said locking relay when its associated terminal is connected to a magneto line.

3. In a telephone system comprising lines of two different characters, a universal cord circuit for interconnecting any two of said lines, answering and calling connecting terminals for said cord circuit, a supervisory signal individual to each end of the cord, a supervisory relay individual to each end of the cord, a locking relay,

and switching means adapted to connect each supervisory relay to control its respective supervisory signal when their associated connecting terminal is connected to a line of the first character and to connect said relay to control the initial energizing circuit for said locking relay when its associated terminal is connected to a line of the second character, said locking relay controlling said respective supervisory signal.

a. In a telephone system comprising magneto and common battery telephone lines, a universal cord circuit for interconnecting any two of said lines, answering and calling connecting terminals for said cord circuit, a supervisory signal individual to each end or" the cord, a supervisory relay individual to each end of the cord, a looking relay, and switching means adapted to connect each supervisory relay to control its respective supervisory signal when their associated connecting terminal is connected to a common battery line and to connect said relay to control the initial energizing circuit for said locking relay when its associated terminal is connected-to a magneto line,-said locking relay controlling said respective supervisory signal.

5. In a telephone system comprising lines of two different characters, a'universal cord circuit for interconnecting any two of said lines, answering and calling connecting terminals for said cord circuit, a supervisory signal individual to each end of the cord, a supervisory relay individual to each end of the cord, a locking relay, a third signal controlled thereby, and switching means adapted to connect each supervisory relay to control its respective supervisory signal when their associated connecting terminal is connected to a line of the first character and to connect said relay to control the initial energizing circuit for said locking relay when its associated terminal is connected to a line of the second character.

6. In a telephone system comprising a magneto and common battery telephone lines, a universal cord circuit for interconnecting any two of said lines, answering and calling connecting terminals .for said cord circuit, a supervisorysignal individual to each end of the cord, a supervisory relay individual to each end of the cord, a looking relay, a third signal controlled thereby, and switching means adapted to connect each supervisory relay to control its respective supervisory signal when their associated connecting terminal is connected to a common battery line and to connect said relay to control the initial energizing circuit for said locking relay when its associated terminal is connected to a magneto line.

7. In a telephone system, a universal cord circuit adapted to interconnect lines of like or of unlike character, answering and calling connecting terminals for said cord circuit, answeringand calling supervisory relays associated with said terminals, respectively, answering and calling supervisory signals controlled by said relays, a locking relay, signal means controlled thereby, and means to delay operation of the locking relay comprising an energizing circuit for said relay including contacts of one of said supervisory relays whereby said locking relay operates only after the operation of said supervisory relay.

8. In a telephone system, a universal cord circuit for interconnecting magneto and common battery lines, answering and calling connecting terminals for said cord circuit, answering and calling supervisory relays individual to said terminals, answering and calling supervisory signals controlled by said relays, a magneto signal, an electromagnet controlling said signal, and circuit means to operate said eleci'romagnet only in response to the operation of one of said supervisory relays. I

9. In a telephone system, a universal cord circuit for interconnecting lines of like or of unlike character, answering and calling connecting terminals for said cord circuit, tip and ring talking conductors connecting said terminals, 145 answering and calling supervisory signals, answering and calling supervisory relays normally bridged across the tip and ring conductors at their respective terminals, an electromagnet normally energized in response to the operation of either of said supervisory relays, signal means controlled thereby, a switching relay associated with each terminal responsive to the connection of said terminal to a line of a first character to open the initial energizing circuit for said eleciromagnet and to connect talking battery to the cord talking conductors through the Windings of its associated supervisory relay, the energizing circuit for each supervisory signal being completed through contacts of its associated. supervisory relay only in response to: the con nection of the associated terminal to a line of the first character.

10. In a telephone system, a universal cord circuit for interconnecting magneto and common battery telephone lines, answering and calling connecting terminals forsaid cord circuit, a supervisory lamp individual to each end of the cord, a supervisory relay individual to each end of the cord, each of said relay controlling its associated lamp only when the associated terminal is connected to a common battery line, av switching relay associated with each said terminal, said relay being energized responsive to the connection of the terminal to, a common battery line, an auxiliary locking relay, a signal controlled thereby, an initial energizing circuit for said relay including a front contact of one of said supervisory relays and a back contact of its associated switching relay.

WIRT E. DARROW. 

